LAB 4 MOLECULAR CELL BIOLOGY structure and charecterestics

LAB (4) MOLECULAR CELL BIOLOGY

structure and charecterestics Nucleic acid Definition : Macromolecules, found in eukaryotic cell nucleus (This is where it got its name). There are 2 types of nucleic acids: (1) Deoxyribonucleic acid (DNA) (2) Ribonucleic acid (RNA), many types of RNA. The building block for nucleic acids is Nucleotide

Comparison between DNA and RNA : Comparison DNA RNA Found in Nucleus and cytoplasm Pentose Deoxyribose Ribose Adenin - Thymin Adenine - Uracil Guanin - Cytocin (Double ) helix One strand of polynucleotides Nitrogenous bases Shape Messenger (m. RNA) Types - Transfer (t. RNA) Ribosomal (r. RNA) m. RNA delivers messege from Function Genetic material that DNA to r. RNA, t. RNA carries makes chromosomes. anticoding for amino acids for r. RNA to make the protein.

Experiment (1) Detection of RNA components in yeast: Steps: 1) in mortar, put 5 g of yeast with equal amount of fine sand 2 - Crush the mix. Add 15 ml of 0. 2% Na. OH solution, then continue crushing till mixture becomes smooth.

3 - Put the mixture in conical flask, wash the mortar with small amount of Na. OH and add it to flask content. Then complete the final volume to 50 ml of Na. OH. 4 - Heat the flask content in water bath for 30 min. Then filtrate the mixture with clothe in a glass cone. Leave the liquid filtrate to cool (and dispose the clothe with precipitant). 5 - Add 20 ml of sulfuric acid (10%), then heat in water bath for 10 min. 50 ﻣﻞ

1) Detection of Purine bases Adenine (A), Guanine (G) - In test tube, put 2 ml of sample previously prepared and add 3 ml of ammonia solution (10%) and few drops of Ag. NO 3 solution(3%). Observation Conclusion White precipitant (+) presence of Purines 2) Detection of Ribose - In test tube add 1 ml of sample with 3 ml of Benedict reagent. Then heat tube in hot water bath for 10 min with shaking. Observation Conclusion Brick red (or brown) (+) presence of ribose sugar 3 -Detection of Phosphate group In test tube add 1 ml of sample with 2 ml of diluted nitric acid (10%) and 2 ml of ammonium molybdate solution, then put tube in hot water bath for 10 min. Observation Conclusion Yellow color (+) presence of phosphate